Benedikt C Spies1, Alexander Fross2, Erik Adolfsson3, Aimen Bagegni2, Sam Doerken4, Ralf-Joachim Kohal2. 1. Medical Center - University of Freiburg, Center for Dental Medicine, Department of Prosthetic Dentistry, Faculty of Medicine, University of Freiburg, Hugstetter Str. 55, 79106 Freiburg, Germany; Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Prosthodontics, Geriatric Dentistry and Craniomandibular Disorders, Aßmannshauser Str. 4-6, Berlin, Germany. Electronic address: benedikt.spies@charite.de. 2. Medical Center - University of Freiburg, Center for Dental Medicine, Department of Prosthetic Dentistry, Faculty of Medicine, University of Freiburg, Hugstetter Str. 55, 79106 Freiburg, Germany. 3. Swerea IVF AB, Argongatan 30, 431 53 Mölndal, Sweden. 4. Medical Center - University of Freiburg, Institute of Medical Biometry and Statistics, Faculty of Medicine, University of Freiburg, Stefan-Meier-Str. 26, 79104 Freiburg, Germany.
Abstract
OBJECTIVE: To investigate the long-term stability of a metal-free zirconia two-piece implant assembled with a carbon fiber-reinforced (CRF) screw by means of transformation propagation, potential changes in surface roughness, the gap size of the implant-abutment connection, and fracture load values. METHODS: In a combined procedure, two-piece implants made from alumina-toughened zirconia were dynamically loaded (107 cycles) and hydrothermally aged (85°, 60days). Implants made from titanium (Ti) and a titanium-zirconium (TiZr) alloy with a titanium abutment screw served as control. Transformation propagation (ATZ) and gap size of the IAC were monitored at cross-sections by scanning electron microscopy (SEM). Furthermore, changes in surface roughness of ATZ implants were measured. Finally, implants were statically loaded to fracture. Linear regression models and pairwise comparisons were used for statistical analyses. RESULTS: Independent of the implant bulk material, dynamic loading/hydrothermal aging did not decrease fracture resistance (p=0.704). All test and control implants fractured at mean loads >1100N. Gap size of the IAC remained stable (<5μm) or decreased. None of the CFR screws fractured during static or dynamic loading. Monoclinic layer thickness of ATZ implants increased by 2-3μm at surfaces exposed to water, including internal surfaces of the IAC. No changes in surface roughness were observed. SIGNIFICANCE: Combined hydrothermal aging and dynamic loading did not affect the above-mentioned parameters of the evaluated two-piece ATZ implant. Mean fracture loads >1100N suggest a reliable clinical application.
OBJECTIVE: To investigate the long-term stability of a metal-free zirconia two-piece implant assembled with a carbon fiber-reinforced (CRF) screw by means of transformation propagation, potential changes in surface roughness, the gap size of the implant-abutment connection, and fracture load values. METHODS: In a combined procedure, two-piece implants made from alumina-toughened zirconia were dynamically loaded (107 cycles) and hydrothermally aged (85°, 60days). Implants made from titanium (Ti) and a titanium-zirconium (TiZr) alloy with a titanium abutment screw served as control. Transformation propagation (ATZ) and gap size of the IAC were monitored at cross-sections by scanning electron microscopy (SEM). Furthermore, changes in surface roughness of ATZ implants were measured. Finally, implants were statically loaded to fracture. Linear regression models and pairwise comparisons were used for statistical analyses. RESULTS: Independent of the implant bulk material, dynamic loading/hydrothermal aging did not decrease fracture resistance (p=0.704). All test and control implants fractured at mean loads >1100N. Gap size of the IAC remained stable (<5μm) or decreased. None of the CFR screws fractured during static or dynamic loading. Monoclinic layer thickness of ATZ implants increased by 2-3μm at surfaces exposed to water, including internal surfaces of the IAC. No changes in surface roughness were observed. SIGNIFICANCE: Combined hydrothermal aging and dynamic loading did not affect the above-mentioned parameters of the evaluated two-piece ATZ implant. Mean fracture loads >1100N suggest a reliable clinical application.
Authors: Frank Akito Spitznagel; Marc Balmer; Daniel B Wiedemeier; Ronald Ernst Jung; Petra Christine Gierthmuehlen Journal: Clin Oral Implants Res Date: 2021-11-05 Impact factor: 5.021